RESUMEN
For a long time Marais's model has been the main tool for disinfection prediction in waste stabilization ponds (WSPs), although various authors have developed other disinfection models. Some ten other empirical models have been listed over the past fifteen years. Unfortunately, their predictions of disinfection in a given pond are very different. The existing models are too empirical to give reliable predictions: often their explanatory variables were chosen arbitrarily. In this work, we try to demonstrate that if influent variables have daily variations, the use of their average values in simulations may overestimate the disinfection effect. New methods are thus needed to provide better fittings of the models. Better knowledge of the mechanisms involved is needed to improve disinfection models.
Asunto(s)
Desinfección/métodos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Algoritmos , Simulación por Computador , Desinfectantes/farmacología , Concentración de Iones de Hidrógeno , Cinética , Modelos Estadísticos , Factores de Tiempo , Agua/química , Movimientos del Agua , Contaminantes Químicos del AguaRESUMEN
The Mèze stabilisation pond system has been monitored over more than 20 years. Despite the enlargement of the plant, the organic load doubled between the early 1980s and recent years, the removal of organic matter and nutrients has been maintained at the same level for COD and increased for BOD5, N and P. Combining anaerobic, step-fed aerated and maturation ponds and multiplying the number of cells resulted in a significant improvement in the performances of the plant. Respectively 34, 24 and 23% of the applied COD was eliminated in the anaerobic, the step-fed and the first three maturation ponds, while the figures for BOD5 were 47, 26, and 19% respectively. 38% of the applied nitrogen was eliminated in the first three maturation ponds. Nitrification and denitrification seem to be a major process of nitrogen removal in warm periods. Most of the phosphorus removal was observed to take place in the two polishing ponds.
Asunto(s)
Reactores Biológicos , Nitrógeno/análisis , Compuestos Orgánicos/análisis , Fósforo/análisis , Aguas del Alcantarillado/microbiología , Biodegradación Ambiental , Escherichia coli/aislamiento & purificación , Escherichia coli/metabolismo , Fermentación , Residuos Industriales , Cinética , Nitratos/química , Nitratos/metabolismo , Nitritos/química , Nitritos/metabolismo , Oxígeno/química , Oxígeno/metabolismo , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodosRESUMEN
The WSP system serving Mèze and Poussan (French Mediterranean coast) was constructed in 1980 and enlarged and upgraded from 1994 to 1998. Water quality along the waste stabilisation pond to (WSP) system has been monitored over the years, thus allowing us to assess the influence of enlargement and upgrading works. A significant enhancement of the average microbiological quality of the effluent was observed, with respective E. coli and streptococci average abatements of 4.1 and 3.4 log. units. Former seasonal variations of microbiological removal have vanished. The contribution of the different ponds to the disinfection performance of the WSP system was analysed. A microbiological quality model was proposed to evaluate the die-off kinetics related to the different ponds and as a tool for the design and management of WSP systems. Though the relationships between die-off coefficients and environmental factors appeared somewhat frail, this modelling is considered a promising approach for the prediction of WSP microbiological performance.